Agitating apparatus



Sept. 20, 1938. w. N. HEATH AGIY ATING APPARATUS Filed Oct. 20, 1936 Patented Sept. 20, 1938 UNITED STATES PATENT OFFICE AGITATING APPARATUS Application October 20, 1936, Serial No. 106,589

11 Claims.

The present invention consists in an improved apparatus for use in applying a metallic reflecting surface to glass articles such as lamp bulbs. An important field of use is in the application of metallic silver coatings to the inside surface of lamp bulbs and for purposes of illustration the invention will be described in that connection.

Many attempts have been made heretofore to provide an inside silveredsurface for lamp bulbs, but serious difiiculties have been encountered and prior to the present invention no commercially successful process has been available. Consequently resort has been had to the application to lamp bulbs of an outside coating of silver. An outside silver coating is noticeably less efficient as a reflector than an inside coating because of the fact that the light must pass twice through the glass in reaching and leaving the reflecting surface. This loss of course, is eliminated in the case of an inside reflecting surface. Further, the outside reflecting surface is likely to become damaged or scratched in use. In fact, this danger is so pronounced that it is the practice to protect outside reflecting surfaces, as heretofore I used, .by a shell of copper or the like and this expedient introduces another problem because in time the copper tends to diffuse into the silver and impair its reflecting efficiency.

On the other hand, it is difficult to secure a smooth continuous and tightly adherent silver coating upon the inside of the bulb on account of the severe treatment imparted to the bulb in lamp manufacture and use. In the first place, it is necessary to remove every particle of occluded air or gas from the walls of the bulb before depositing the silver coating thereon, because if any gas is left beneath the silver coating, it will expand and rupture the coating when the bulb is exhausted prior to the sealing step, thus damaging the reflecting surface.

Where a silver-depositing solution is employed it also becomes important to prevent contact with the walls to be plated of precipitate which may be formed in the solution as a result of secondary reactions or otherwise. If such precipitate is allowed to settle against the walls the silver will not subsequently unite with the glass in the contacted spots and pin holes or imperfections in coating will result. Further problems arise on account of intense heat developed within the bulb under conditions of use, caused by the concentrated heat rays reaching the reflecting surface of the bulb.

The problem of preventing contact or settling of precipitate in the silver-depositing solution upon the walls of the bulb I have solved by only partially filling the bulb with the solution and then imparting a special movement of predetermined character to the bulb, such that the solution is caused to flow or slosh continuously across the surfaces to be treated, and a liquid film is thus interposed at all times between the glass and the precipitate and consequently no detrimental contact occurs.

The difliculties above described have been successfully solved in accordance with the method disclosed in the application of Pincus Deren, Ser. No. 42,227, September 26, 1935. The subject matter of the present invention is an apparatus by which the method of the above application may be best put into practice under commercial conditions of lamp manufacture.

As herein shown the apparatus comprises a bulb-holding device in combination with means for imparting thereto a movement such that metal-precipitating solution in the bulb or bulbs is maintained in a state of continuous agitation, flowing across the bulb surface in a constantly changing path and never permitting the secondary deposit to settle upon the glass walls of the bulbs. The desired results may be secured as herein shown by moving the bulbs being treated transversely in a circular path and simultaneously moving them axially or longitudinally and also rotating them about their own axes. Preferably these motions may also be combined with a wabbling or swaying motion about their longitudinal axes. All of these different component movements may be, and preferably are, modified by the interposition of yielding means in the operating train of the bulb-holder so that the bulbs lag behind or overthrow the movements of the actuating elements.

The apparatus herein shown comprises a base member and a bulb-holding plate yieldingly supported thereon in spaced relation. To the base member is imparted movement in a circular path in its own plane, that is to say,. a movement of equal longitudinal and transverse components so that each point of the base member moves in a horizontal circle of perhaps one half inch in diameter. Combined with this circular movement the base member also partakes of a vertical movement, each end thereof being raised and lowered perhaps one-half inch in each cycle. The movement of the base member may be cyclic in that the lateral and vertical movements thereof occur in definitely timed relation. However, the bulb-holding plate is yieldingly supported upon the base member and its movements are not cyclic but vary in accordance with the action of the springs under different conditions of load and movement of the liquid solutions in the bulbs thereon. v

The bulb-holding plate as herein shown is equipped with a series of sockets in which the individual bulbs may be mounted in stoppered and inverted condition with the silver depositing solution therein. The sockets may be so designed and their connection with the stoppered bulbs so arranged that the bulbs are free to rotate about their own longitudinal axes. Under the conditions of movement above explained, it has been discovered that the bulbs will of their own accord rotate slowly'in a reverse direction to the circular movement imparted to the bulbholding plate. If desired this connection between the sockets of the bulb-holding plate and the bulbs may be designed to permit the bulbs also to partake of a wabbling or swaying motion about a vertical axis, thus further contributing to cause the flow of the silver precipitating solution to take place in an irregular and noncyclic path.

The invention includes within its scope a novel combined stopper and support for the individual bulbs. The problem of tightly stoppering the inverted bulbs without breaking them, but so effectively as to prevent leakage of the silver precipitating solution presents many diificulties. These have been solved however, by providing a holder which includes one or more soft rubber washers which may be inserted in the neck of the bulb and then expanded into engagement with its wall by relative longitudinal movement of the holder parts. In this connection an important feature of the invention consists in a holder for an inverted bulb having a well or depression in its inner end in which the precipitate formed in the solution may collect during the process, and thus be prevented from settling against portions of the bulb which it is desired to coat by deposition from a continuously flowing solution.

These and other features of the invention will be best understood and appreciated from the following description of a preferred embodiment thereof, selected for purposes of illustration and shown in the accompanying drawing in which- Fig. 1 is a view in perspective of the apparatus, parts thereof being shown as broken away,

Fig. 2 is a view in elevation showing a stoppering and holding device, and

Fig. 3 is a view in elevation of-one of the supporting posts of the base member.

As herein shown the apparatus is mounted upon a stationary support l by. means of four standards each having a' flange II and a stationary barrel l2. The standards directly support the base member 22 of the apparatus and upon this is mounted the bulb-holding plate 30. Each of the barrels l2 carries on its upper end a vertical thrust bearing l3 above which is cated a collar l4 fast to a vertical shaft i5 which is journalled in the barrel l2 of the standard. The shaft l5 and the collar member M are rotated through the medium of a sprocket wheel l6 which is fast upon the collar member and is arranged to mesh with a sprocket chain 29, to be hereinafter described.

A vertical pin I1 projects upwardly from the collar member ll of each standard and is arranged eccentrically with respect to the axis of the shaft l5. Each pin I'I extends through a bushing in a horizontal bracket 23 secured to one corner of the base member 22, the bushing being formed with spaced collars l9 and 2| which engage opposite faces of the bracket. The collars H are all set with the pins H, in the same angular position and consequently their rotation' is transmitted to the base member 22 as a circular movement in a horizontal plane.

Each bushing with itscollars l9 and 2| is freely slidable upon its eccentric pin i1 and from each of the lower collars l9 extends a supporting pin which rests upon the face of a cam i8 secured 'to the pin l1. Each cam I8 has an abrupt throw of perhaps a half inch and in its rotation it periodically lifts one corner of the member 22 and then allows it to fall by gravity. It will be noted that the supporting pin 20 is shifted laterally with the rotation of the eccentric pin l1 and that portion of the base member 22 to which its lateral movement is transmitted so that its operative relation to the cam I8 is not disturbed, in other words, both the cam l8 and the supporting pin 20 rotate about the axis of the eccentric pin I1 and in addition to this rotation they are moved bodily in a path concentrio with the axis of the shaft IS.

The four sprocket wheels [6 upon their respective standards are driven simultaneously at a uniform rate of speed by the sprocket chain 29 which in turn is driven by a sprocket wheel 28 upon the upper end of the vertical shaft of a reducing gear unit 21 which is bolted to the stationary support I 0 in any convenient position beneath the base member 22. The reducing gear unit 21 is driven by a motor also secured to the support I0 and having a. driving belt 26. All the cams 18 are set in the same angular position, while the pins 20 located at one end of the base are set 180 degrees in advance of the pins located at the other end of the base. The result is that in the rotation of these cams one end of the base 22 is being lifted while the other end is being lowered and accordingly a continuous rocking movement is imparted thereto and this, as already explained, is combined with the component of circular movement imparted to the base by the eccentric pins IT.

The bulb-holding plate 30 is yicldingly supported above the base member 22 and in'spaced relation thereto by four compression springs 3|, one located near each corner of the plate. The upper end of each of these springs is secured in place by a screw 32. In order to check the rebound of the plate 30 a chain connection 33- is provided between the base member 22 and the plate 30 adjacent to each of the springs 3|. The plate 30 is further provided with a plurality of sockets 34 arranged in spaced rows, as for example, four rows of six socketseach.

The bulbs are presented to the bulb-holding plate 30 stoppered and in inverted position and partially filled with a silver precipitating solution. One of the combined stoppering and bulbsupporting elements is shown in Fig. 2 and this will now be described. It comprises first a central shaft 35 to which is pinned a fixed sleeve member 31 having a collar 36 at its lower end and a radially projecting pin. Supported upon the fixed sleeve 31 is a rotatable cam sleeve 38 also having a radial pin. Above the cam sleeve 38 is a loose sleeve 39 having a spline connection with the shaft 35. interposed between the upper end of the loose sleeve 39 and a head 40 formed upon the upper end of the shaft 35 is a pair of rubber washers 42. A

The sleeve 39 is also provided with a soft rubber bushing 43 arranged tofit in the open end of the bulb neck. The construction is such that after the silver-precipitating solution has been supplied to the bulb the end of the stoppering element may be inserted into the neck thereof while the bulb is held right side up and then by turning the cam sleeve 38, thewashers 42 are compressed and caused to expand into liquidtight engagement with the walls of the bulb neck. The bulb thus stoppered may now be inverted and the end of the spindle 35 inserted in one of the sockets 34. This is usually done by the operator while the bulb-holding plate 30 is in motion so that a turbulent agitation is at once imparted to the solution in the bulb. It will be noted that, as shown in Fig. 2, the spindle 35 projects fully into the socket 34 permitting the weight of the assembled bulb and stoppering element to be supported by thecollar 36 and as it rests upon the flange of the socket. The spindle 35 however, fits loosely in the socket so that not only is the bulb assembly permitted to rotate about its longitudinal axis, but also to partake of a Wabbling or swaying motion within some such limits as indicated by the dash lines in Fig. 1.

A portion of the metallic silver deposited from the solution does not adhere to the walls of the bulb but collects in the neck thereof and may interfere to some extent with the formation of a smooth continuous surface in the neck of the bulb. In order to prevent this as far as possible the head 40 of the stoppering element is provided with a well ill and in this the precipitate tends to collect, thus being prevented from piling up against the walls of the neck.

The nature of the movement imparted to the base member 22, as already explained, is a cyclic or uniform movement having components transverse to the bulb axis and in the direction of the bulb axis and on account of its timing including also a rocking component. The bulb-holding .plate 30 partakes of all these movements, but in a modified and more or less irregular fashion on account of its spring connection with the base member 22. The bulb stoppering and supporting element is held for free rotation in the socket 34 and in practice it is found that the bulb with this element will revolve slowly in a rotary direction opposite to that imparted to the plate, that is, if the movement imparted to the plate is in an anti-clockwise direction as suggested by the circle in dash lines in Fig. 1, then the rotation of the bulb itself will be in a clockwise direction as indicated by the arrow in the same figure. The result of all these movements is to impart to the silver precipitating solution an irregular whirling flow carrying it over all parts of the inner surface of the bulb in an irregular manner with the result that a continuous coating of metallic silver is deposited upon the bulb surface, the coating being of uniform thickness throughout and free of pin holes or other imperfections. It

is contemplated that even further irregularities may be introduced into the movement of the bulb-holding plate 30 by fitting the bushings carrying the collars l9 and 2| loosely in the brackets 23 or by fitting the pins I1 loosely in the bushings. All such expedients tend to prevent the plate 30 and the bulbs thereon from moving in a regular or cyclic manner and cause the current of the silver-depositing solution to fiow always in an irregular manner upon the walls of the bulbs.

The nature and scope of the invention having been indicated and a preferred embodiment thereof specifically described, what is claimed as new is:

l. A device of the class described comprising a holder for lamp bulbs containing metal-precipitating solution, means for mounting an inverted bulb thereon with its larger end free to sway and rotate, and means for imparting to the holder and the bulbs supported thereon a combined movement transverse tothe axis of the bulb and holder, a socket and spindle for supporting a lamp bulb on said holder for free rotation about its own axis, and means for imparting to the holder an up-and-down .movement combined with a sidewise movement such that the bulb is caused to rotateas the holder is moved.

4. A device of the class described comprising a holder for supporting a lamp for free rotation about its own axis and for a swaying motion about one end, and means-for imparting to the holdera rocking up-and-down movement combined with circular sidewise movement.

5. A device of the class described comprising a base member mounted for continuous movement having combined vertical and horizontal components of fixed magnitude, a bulb-holding plate supported on the base for yielding movement in respect thereto, and sockets located on said plate.

6. A device of the class described comprising a plate having a plurality of sockets, in combination with bulb stoppering and holding elements shaped to fit loosely in said sockets.

7. A device of the class described comprising a plate having a plurality of sockets, in combination with bulb stoppering and holding elements each having an expansible portion to fit the neck of a bulb, and a cylindrical portion to fit freely in one of said sockets.

8. A device of the class described comprising a plate having a series of sockets, in combination with bulb stoppering and holding elements each having an elongated spindle with a head adapted to be inserted into the bulb neck, an expansible section and a lower end shaped to fit freely in one of said sockets, and means located outside the bulb neck for expanding said section to close the bulb.

9. A device of the class described comprising a base member, means for supporting said member at separated points and for imparting to each point a rising and falling movement combined with a lateral rotary movement, a bulb supporting plate mounted above the base member upon springs, and spaced sockets in said plate.

10. In apparatus of the class described, the combination of a bulb-holder having a socket and means for imparting a continuous agitating movement to the. holder, with a device having an expansible bulb-stoppering section arranged to be positioned within the neck of the bulb and an elongatedstem shaped to make said socket.

11. In apparatus of the class described, a combined bulb stoppering and supporting element including a spindle having an open well sunk in its upper end, an expansible section in the element located below the opening of said well, and means arranged to be operated from outside the bulb-for expanding said section within the bulb neck without affecting the well in said spindle.

WALTER N. HEATH.

a rotary fit in 

